Step 1: Divide the number into separate digits:
07002 => 0 7 0 0 2
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
0 to 7 = 7
7 to 0 = 7
0 to 0 = 0
0 to 2 = 2
2 to 0 = 2
Step 3: Combine the filters to a string:
7 7 0 2 2 = 77022